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A051683
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Triangle read by rows: a(n,k)=n!*k.
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17
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1, 2, 4, 6, 12, 18, 24, 48, 72, 96, 120, 240, 360, 480, 600, 720, 1440, 2160, 2880, 3600, 4320, 5040, 10080, 15120, 20160, 25200, 30240, 35280, 40320, 80640, 120960, 161280, 201600, 241920, 282240, 322560, 362880, 725760, 1088640, 1451520
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table;
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refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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COMMENTS
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Numbers with only one nonzero digit when written in base factorial. - Franklin T. Adams-Watters, Nov 28 2011
In other words, numbers n such that A034968(n) = A099563(n). - Antti Karttunen, Jul 02 2013
When the numbers denote finite permutations (as row numbers of A055089) these are the circular shifts to the right within an interval. The subsequence A001563 denotes the circular shifts that start with the first element. Compare A211370 for circular shifts to the left. - Tilman Piesk, Apr 29 2017
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LINKS
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Reinhard Zumkeller, Rows n=1..150 of triangle, flattened
Tilman Piesk, Circular shifts to the right (Arrays of permutations)
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FORMULA
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a(n) = A000142(A002024(n)) * A002260(n) = A002024(n)! * A002260(n). - Antti Karttunen, Jul 02 2013
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EXAMPLE
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Table begins
1
2 4
6 12 18
24 48 72 96 ...
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MATHEMATICA
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a[n_, k_] := n!*k; Flatten[Table[a[n, k], {n, 9}, {k, n}]] (* Jean-François Alcover, Apr 22 2011 *)
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PROG
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(Haskell)
a051683 n k = a051683_tabl !! (n-1) !! (k-1)
a051683_row n = a051683_tabl !! (n-1)
a051683_tabl = map fst $ iterate f ([1], 2) where
f (row, n) = (row' ++ [head row' + last row'], n + 1) where
row' = map (* n) row
-- Reinhard Zumkeller, Mar 09 2012
(Scheme): (define (A051683 n) (* (A000142 (A002024 n)) (A002260 n))) -- Antti Karttunen, Jul 02 2013
(MAGMA) [[Factorial(n)*k: k in [1..n]]: n in [1..15]]; // Vincenzo Librandi, Jun 15 2015
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CROSSREFS
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Cf. A000142, row sums give A001286(n+1).
Cf. A007623, A200748, A162608, A001563.
Sequence in context: A181416 A225566 A273009 * A215821 A192096 A181740
Adjacent sequences: A051680 A051681 A051682 * A051684 A051685 A051686
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KEYWORD
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easy,nice,nonn,tabl
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AUTHOR
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Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de)
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STATUS
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approved
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